A wide variety of coatings have been used to coat the surfaces of packaging articles (e.g., food and beverage containers). For example, metal cans are sometimes coated using “coil coating” or “sheet coating” operations, i.e., a planar coil or sheet of a suitable substrate (e.g., steel or aluminum metal) is coated with a suitable composition and hardened (e.g., cured in an oven). The coated substrate then is formed into a can end or body. Alternatively, liquid coating compositions may be applied (e.g., by spraying, dipping, rolling, etc.) to the formed article and then hardened (e.g., cured in an oven).
Packaging coatings should preferably be capable of high-speed application to the substrate and provide the necessary properties when hardened to perform in this demanding end use. For example, the coating should be safe for food contact, have excellent adhesion to the substrate, and resist degradation over long periods of time, even when exposed to harsh environments.
Many current packaging coatings suffer from one or more performance defects and/or contain extractable quantities of one or more undesirable compounds.
From the foregoing, it will be appreciated that what is needed in the art is a packaging container (e.g., a food or beverage container), particularly one that is coated with a composition that does not contain extractable quantities of undesirable compounds.